Phase7: Void/Refund logic

src/app/api/stripe/webhook/route.ts

@@ -2,11 +2,14 @@ import { NextResponse } from "next/server";
 import type Stripe from "stripe";
 import { getStripeClient, getWebhookSecret } from "@/lib/stripe";
 import {
+  getInvoiceByStripePaymentIntent,
+  isStripeRefundRecorded,
   markInvoicePaid,
   markStripeEventProcessed,
   setInvoiceStripePaymentIntent,
   tryRecordStripeEvent,
 } from "@/lib/db";
+import { refundInvoice, RefundNotAllowedError } from "@/lib/billing";
 
 /**
  * POST /api/stripe/webhook
@@ -209,13 +212,103 @@ async function handleCheckoutCompleted(
 }
 
 async function handleChargeRefunded(charge: Stripe.Charge): Promise<void> {
-  // v1 scope: log only. Refunds always go through Stripe → admin
-  // initiates them in the dashboard. Updating our invoice status
-  // to 'void' or partial-credit needs more product thinking
-  // (partial refunds? credit notes? VAT corrections?). Phase 7.
-  console.log(
-    `Charge ${charge.id} refunded (amount ${charge.amount_refunded} ${charge.currency}); no portal-side state change.`
-  );
+  // Phase 7: mirror Stripe refunds into the portal so credit notes
+  // are issued for refunds initiated in the Stripe Dashboard. For
+  // refunds initiated via /api/admin/.../refund, this handler is a
+  // no-op (each refund's stripe_refund_id is already recorded
+  // before the webhook lands — refundInvoice records it
+  // synchronously after the Stripe API call).
+  //
+  // A charge can have multiple refund objects (multiple partial
+  // refunds against the same charge accumulate here). We iterate
+  // and process any that aren't yet recorded in our DB.
+  const paymentIntentId =
+    typeof charge.payment_intent === "string"
+      ? charge.payment_intent
+      : charge.payment_intent?.id;
+  if (!paymentIntentId) {
+    console.error(
+      `charge.refunded for charge ${charge.id} has no payment_intent; cannot link to invoice.`
+    );
+    return;
+  }
+  const invoice = await getInvoiceByStripePaymentIntent(paymentIntentId);
+  if (!invoice) {
+    console.error(
+      `charge.refunded for payment_intent ${paymentIntentId} has no matching invoice; ignoring.`
+    );
+    return;
+  }
+  const refundsList = charge.refunds?.data ?? [];
+  if (refundsList.length === 0) {
+    // Some charge.refunded events fire with the refunds list
+    // collapsed (the object includes the aggregated amount_refunded
+    // but the data array can be omitted depending on Stripe's
+    // expansion choices). In that case there's nothing for us to
+    // iterate over here; the actual `refund.created` /
+    // `refund.updated` events carry per-refund detail and we'd need
+    // to enable those in Stripe to handle them. For v1 we log and
+    // rely on the in-portal admin path (refundInvoice) being the
+    // only refund initiator.
+    console.log(
+      `charge.refunded for charge ${charge.id} arrived without refund objects in data; in-portal flow assumed.`
+    );
+    return;
+  }
+  for (const refund of refundsList) {
+    try {
+      // Idempotency: skip refunds we already recorded (either via
+      // portal admin action or a prior webhook delivery).
+      if (await isStripeRefundRecorded(refund.id)) {
+        continue;
+      }
+      const amountChf = (refund.amount ?? 0) / 100;
+      if (amountChf <= 0) continue;
+      // Map Stripe refund status to ours. Anything other than the
+      // canonical four falls through to 'pending' so we don't lose
+      // the record entirely.
+      let status: "pending" | "succeeded" | "failed" | "canceled" = "pending";
+      if (refund.status === "succeeded") status = "succeeded";
+      else if (refund.status === "failed") status = "failed";
+      else if (refund.status === "canceled") status = "canceled";
+      // For refunds that originated in Stripe Dashboard we don't
+      // have a reason to display. Use a sentinel string so the
+      // credit note PDF has something to print. Admin can edit
+      // post-hoc if needed (no UI for that today, but the DB row
+      // is reachable).
+      const reason = refund.reason
+        ? `Stripe Dashboard: ${refund.reason}`
+        : "Refund issued via Stripe Dashboard";
+      // refundInvoice with existingStripeRefund: don't call Stripe
+      // again (we'd error since the refund already exists), just
+      // mirror the record into our DB and issue the credit note.
+      await refundInvoice({
+        invoiceId: invoice.id,
+        amountChf,
+        reason,
+        refundedBy: "stripe-webhook",
+        existingStripeRefund: { id: refund.id, status },
+      });
+      console.log(
+        `Mirrored Stripe refund ${refund.id} for invoice ${invoice.invoiceNumber} (CHF ${amountChf.toFixed(2)}).`
+      );
+    } catch (e) {
+      if (e instanceof RefundNotAllowedError) {
+        // The invoice was already fully refunded by an earlier
+        // webhook delivery or by an in-portal action. That's fine.
+        console.log(
+          `Stripe refund ${refund.id}: ${e.message} (already accounted for).`
+        );
+        continue;
+      }
+      // For any other error, log but continue to the next refund —
+      // we don't want one bad refund to block the rest.
+      console.error(
+        `Failed to mirror Stripe refund ${refund.id} for invoice ${invoice.invoiceNumber}:`,
+        e
+      );
+    }
+  }
 }
 
 async function handlePaymentFailed(